Question 1

2pts

(CO 4) From a random sample of 68 businesses, it is found that the mean time that employees spend on personal issues each week is 4.9 hours with a standard deviation of 0.35 hours. What is the 95% confidence interval for the amount of time spent on personal issues?

Group of answer choices

(4.83, 4.97)

(4.71, 5.09)

(4.82, 4.98)

(4.55, 5.25)

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Question 2

2pts

(CO 4) If a confidence interval is given from 8.56 to 10.19 and the mean is known to be 9.375, what is the maximum error?

Group of answer choices

1.630

8.560

0.815

0.408

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Question 3

2pts

(CO 4) If the population standard deviation of a sample decreases without other changes, what is most likely to happen to the confidence interval?

Group of answer choices

cannot determine

narrows

does not change

widens

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Question 4

2pts

(CO 4) From a random sample of 41 teens, it is found that on average they spend 31.8 hours each week online with a population standard deviation of 3.65 hours. What is the 90% confidence interval for the amount of time they spend online each week?

Group of answer choices

(24.50, 39.10)

(28.15, 35.45)

(29.99, 33.61)

(30.86, 32.74)

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Question 5

2pts

(CO 4) A company making refrigerators strives for the internal temperature to have a mean of 37.5 degrees with a standard deviation of 0.6 degrees, based on samples of 100. A sample of 100 refrigerators have an average temperature of 37.53 degrees. Are the refrigerators within the 90% confidence interval?

Group of answer choices

No, the temperature is outside the confidence interval of (37.40, 37.60)

Yes, the temperature is within the confidence interval of (36.90, 38.10)

Yes, the temperature is within the confidence interval of (37.40, 37.60)

No, the temperature is outside the confidence interval of (36.90, 38.10)

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Question 6

2pts

(CO 4) What is the 97% confidence interval for a sample of 104 soda cans that have a mean amount of 12.05 ounces and a population standard deviation of 0.08 ounces?

Group of answer choices

(12.033, 12.067)

(12.035, 12.065)

(11.998, 12.102)

(11.970, 12.130)

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Question 7

2pts

(CO 4) Determine the minimum sample size required when you want to be 98% confident that the sample mean is within two units of the population mean. Assume a standard deviation of 7.55 in a normally distributed population.

Group of answer choices

44

76

77

78

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Question 8

2pts

(CO 4) Determine the minimum sample size required when you want to be 80% confident that the sample mean is within 1.3 units of the population mean. Assume a standard deviation of 9.24 in a normally distributed population.

Group of answer choices

84

195

194

83

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Question 9

2pts

(CO 4) Determine the minimum sample size required when you want to be 75% confident that the sample mean is within thirty units of the population mean. Assume a standard deviation of 327.8 in a normally distributed population

Group of answer choices

157

197

158

324

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Question 10

2pts

(CO 4) In a sample of 8 high school students, they spent an average of 25.8 hours each week doing sports with a standard deviation of 3.2 hours. Find the 95% confidence interval.

Group of answer choices

(23.12, 28.48)

(23.15, 28.50)

(19.40, 32.20)

(22.60, 29.00)

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Question 11

2pts

(CO 4) In a sample of 15 stuffed animals, you find that they weigh an average of 8.56 ounces with a standard deviation of 0.08 ounces. Find the 92% confidence interval.

Group of answer choices

(8.528, 8.591)

(8.516, 8.604)

(8.521, 8.599)

(8.543, 8.577)

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Question 12

2pts

(CO 4) Market research indicates that a new product has the potential to make the company an additional $3.8 million, with a standard deviation of $1.9 million. If this estimate was based on a sample of 10 customers, what would be the 90% confidence interval?

Group of answer choices

(1.90, 5.71)

(2.00, 5.60)

(2.70, 4.90)

(2.51, 5.09)

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Question 13

2pts

(CO 4) Supplier claims that they are 95% confident that their products will be in the interval of 20.45 to 21.05. You take samples and find that the 95% confidence interval of what they are sending is 20.32 to 21.48. What conclusion can be made?

Group of answer choices

The supplier products have a higher mean than claimed

The supplier is less accurate than they have claimed

The supplier is more accurate than they claimed

The supplier products have a lower mean than claimed

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Question 14

2pts

(CO 4) In a sample of 19 small candles, the weight is found to be 3.72 ounces with a standard deviation of 0.963 ounces. What would be the 87% confidence interval for the size of the candles?

Group of answer choices

(3.371, 4.069)

(3.369, 4.071)

(3.199, 4.241)

(3.337, 4.103)

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Question 15

2pts

(CO 4) In a situation where the sample size was decreased from 39 to 29, what would be the impact on the confidence interval?

Group of answer choices

It would remain the same as sample size does not impact confidence intervals

It would become wider due to using the t distribution

It would become narrower with fewer values

It would become narrower due to using the z distribution

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Question 16

2pts

(CO 4) In a random sample of fourteen people, the mean time at lunch was 35.6 minutes with a standard deviation of 8.2 minutes.Assuming the data are normally distributed, what would be the 85% confidence interval?

Group of answer choices

(30.87, 40.33)

(32.25, 38.95)

(32.33, 38.87)

(32.45, 38.75)

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Question 17

2pts

(CO 4) If a confidence interval is known to be (43.83, 46.37), what would be its margin of error?

Group of answer choices

3.54

2.54

0.64

1.27

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Question 18

2pts

(CO 4) A company manufacturers soda cans with a diameter of 52 millimeters.In a sample of 12 cans, the standard deviation was 2.3 millimeters.What would be the 96% confidence interval for these cans?

Group of answer choices

(51.33, 52.67)

(50.45, 53.55)

(50.64, 53.36)

(51.34, 52.66)